A total of 2.4 million cubic metres of subsea dredging has been requested by Peel Ports - a 12-fold increase on the original 150,000 to 200,000m3 which featured in its application to North Ayrshire Council in 2017.
Campaigners Friends of the Firth of Clyde claim that the application could have a drastic impact on the neighbouring Southannan Sands - a site of scientific interest (SSSI).
The new dredging plan came to light last month as a result of a freedom of information request by the group in October last year.
Marine Scotland previously advised the developer that Environmental Impact Assessment (EIA) was not required
However, according to the Scottish government, which responded to the request, that position has now come under review given the proposals for significantly increased dredging volume.
Marine Scotland have declined to accept the most recent license application from the developer, and subsequently met with Peel Ports, who have agreed to submit a further EIA screening request based on these updates.
Peel Ports, which has been approached for comment, said Hunterston is one of Scotland’s most important development sites comprising a 300 acre brownfield footprint, deepwater, and rail connections.
It says the development is expected to support over 1,700 jobs and add over £140m in economic value to Scotland.
The SSSI at Southannan Sands comprises sections which are of “national significance” for intertidal sand flats which are popular grounds for lugworms, crab and shrimp and mussels and cockles, especially on the lower shores.
The sandflats support a variety of wintering, migratory and breeding wildfowl and waders, including species such as shelduck, eider, oystercatcher, lapwing,and redshank.
The habitat is also important for fish species when flooded at high tide.